Benzocaine and lidocaine induced methemoglobinemia after bronchoscopy: a case report

Acute poisoning of copper sulfate: a case report and review literature

Background

Copper sulfate is a bright blue crystal used primarily for agricultural purposes, as a pesticide, disinfectant, feed, and soil additive. Acute volunteer poisoning of copper sulfate is not common in the world and in Iran.

Case presentation

We reported the case of a 15-year-old girl who presented to the emergency department after ingestion of an unknown amount of copper sulfate following a struggle at school. She had become acquainted with the toxic compound through school textbooks. On admission to the hospital, she had abdominal pain and a sore throat with a normal serum copper level. The patient stated that she had three episodes of bluish vomiting. She underwent symptomatic treatment and was monitored for 3 days. The outcome was favorable, and she had no signs and symptoms of organ failure.

Conclusions

As a result, copper sulfate poisoning depending on the consumed dose can be mild or very severe with a high mortality rate. The authors discuss the various pathogenesis and treatments of this rare poisoning by reviewing the available literature.

Oral Chronic Graft-Versus-Host Disease

Chronic oral graft-versus-host disease (cGVHD) is a complex, frequent, and highly impactful complication of allogeneic hematopoietic cell transplantation (alloHCT). It represents the leading cause of morbidity and mortality in long-term alloHCT survivors. cGVHD can affect almost any visceral organ system and commonly affects the skin, eyes and mouth, manifesting with signs and symptoms similar to other known immune-mediated and autoimmune diseases. Oral manifestations of GVHD include inflammation, thinning, and ulceration of oral mucosal tissues (similar to lichen planus), lymphocyte-mediated salivary gland dysfunction (similar to Sjögren/Sicca Syndrome), and decreased oral opening (trismus) secondary to sclerosis of oral and perioral tissues (analogous to limitation in scleroderma). Potential sequelae include severe mucosal pain, compromised nutrition, weight loss, limitation in opening, and sometimes irreversible fibrosis of the salivary glands. While some cases can be managed with topical therapies, management may also require long-term targeted immunosuppressive and/or corticosteroid therapy with associated risk of local and systemic infection, hyperglycemia, kidney dysfunction, osteopenia/osteoporosis, and possibly secondary malignancies. The aim of this mini-review is to provide an up-to-date review of literature related to the diagnosis and management of oral cGVHD to aid dental and medical clinicians in optimizing oral cGVHD therapy while minimizing potential adverse effects.

Methaemoglobinaemia in the perioperative period with regional block

Methaemoglobin is a form of haemoglobin with oxidised ferric (+3) iron rather than ferrous (+2) iron, which causes a leftward shift in the oxyhaemoglobin dissociation curve and prevents oxygen delivery. Anaesthesiologists need to be familiar with this differential diagnosis for hypoxia given the use of drugs in the perioperative setting known to induce methaemoglobinaemia, including benzocaine and lidocaine, antibiotics such as dapsone and anaesthetic gases, including nitric oxide. This case report details an interesting case of symptomatic methaemoglobinaemia in the perioperative period in the setting of dapsone use and an erector spinae block performed with ropivacaine.

Is topical lidocaine beneficial before catheter insertion in esophageal manometry and ambulatory pH monitoring?

BACKGROUND

Conventionally, topical anesthesia is applied to improve the tolerance of esophageal manometry (EM) and ambulatory pH monitoring (apH) but there is presently no evidence supporting this practice. We aimed to compare the tolerance of EM and apH with vs without topical lidocaine anesthesia.

METHODS

A prospective study was conducted at our center between January 2017 and January 2019. All patients who underwent EM or apH and completed a systematically distributed standardized patient survey were included. From January 2017 to June 2018, all patients had a viscous lidocaine solution applied before EM and apH ("lidocaine" group). After June 2018, we ceased applying any topical anesthesia ("no lidocaine" group). Patient-reported adverse effects and satisfaction scores were compared between these two patient groups.

KEY RESULTS

Two hundred forty-nine patient surveys were included. "Lidocaine" (n = 124) and "no lidocaine" (n = 125) groups were similar in age (56.9 ± 14.0 vs 56.0 ± 13.7; P = .77) and gender distributions (65.9% vs 63.3% female; P = .68). Patients in the "lidocaine" group were less likely to report pain during catheter insertion (33.6% vs 50.8%; P = .007, OR: 0.49 [95% CI 0.29-0.83]) and reported a lower overall pain score (2.82 ± 1.38 vs 3.20 ± 1.42 on 5; P = .04). There was a tendency toward increased global satisfaction with lidocaine application but that was not statistically significant (4.36 ± 1.05 vs 4.11 ± 1.13; P = .08). In subgroup analyses, female patients, younger patients, and patients who underwent EM were more likely to benefit from lidocaine application.

CONCLUSIONS AND INFERENCES

Application of topical lidocaine before esophageal motility tests reduces pain during catheter insertion and overall pain.

Office-Based 532-Nanometer Pulsed Potassium-Titanyl-Phosphate Laser Procedures in Laryngology

With fiber-based lasers that may be passed via the working channel of a flexible laryngoscope, in-office laser laryngeal surgery has become possible. The potassium-titanyl-phosphate laser has several features that make it ideal for laryngeal surgery, and it is now the laser of choice for in-office management of a variety of laryngeal lesions. Its applications have expanded significantly since its introduction, with reports of new indications continuing to appear in the literature. This article provides a comprehensive review of the indications and technical details of in-office potassium-titanyl-phosphate laser laryngeal surgery, and a summary of the existing literature regarding outcomes of these procedures.

Neurologic Complications in the Intensive Care Unit

Complications involving the central and peripheral nervous system are frequently encountered in critically ill patients. All components of the neuraxis can be involved including the brain, spinal cord, peripheral nerves, neuromuscular junction, and muscles. Neurologic complications adversely impact outcome and length of stay. These complications can be related to underlying critical illness, pre-existing comorbid conditions, and commonly used and life-saving procedures and medications. Familiarity with the myriad neurologic complications that occur in the intensive care unit can facilitate their timely recognition and treatment. Additionally, awareness of treatment-related neurologic complications may inform decision-making, mitigate risk, and improve outcomes.

Lidocaine-induced methemoglobinemia: a clinical reminder

Methemoglobinemia is a rare condition in which the iron in hemoglobin is stabilized in the ferric (Fe(3+)) form, making it unable to bind oxygen and leading to tissue hypoxia and possibly death. The condition may be hereditary or acquired, the latter resulting from ingestion or application of common oxidizing agents such as lidocaine. As management of methemoglobinemia depends on prompt recognition, clinicians who administer or prescribe oxidizing agents must be aware of the clinical symptoms of methemoglobinemia, including cyanosis, pulse oximetry values that do not respond to increased oxygen delivery, and altered mental status. Currently, methylene blue is the drug of choice for the management of methemoglobinemia.

An evaluation of 10 percent and 20 percent benzocaine gels in patients with acute toothaches: efficacy, tolerability and compliance with label dose administration directions

BACKGROUND

The authors evaluated the efficacy and tolerability of 10 percent and 20 percent benzocaine gels compared with those of a vehicle (placebo) gel for the temporary relief of toothache pain. They also assessed the compliance with the label dose administration directions on the part of participants with toothache pain.

METHODS

Under double-masked conditions, 576 participants self-applied study gel to an open tooth cavity and surrounding oral tissues. Participants evaluated their pain intensity and pain relief for 120 minutes. The authors determined the amount of gel the participants applied.

RESULTS

The responders' rates (the primary efficacy parameter), defined as the percentage of participants who had an improvement in pain intensity as exhibited by a pain score reduction of at least one unit on the dental pain scale from baseline for two consecutive assessments any time between the five- and 20-minute points, were 87.3 percent, 80.7 percent and 70.4 percent, respectively, for 20 percent benzocaine gel, 10 percent benzocaine gel and vehicle gel. Both benzocaine gels were significantly (P ≤ .05) better than vehicle gel; the 20 percent benzocaine gel also was significantly (P ≤ .05) better than the 10 percent benzocaine gel. The mean amount of gel applied was 235.6 milligrams, with 88.2 percent of participants applying 400 mg or less.

CONCLUSIONS

Both 10 percent and 20 percent benzocaine gels were more efficacious than the vehicle gel, and the 20 percent benzocaine gel was more efficacious than the 10 percent benzocaine gel. All treatments were well tolerated by participants. Practical Implications. Patients can use 10 percent and 20 percent benzocaine gels to temporarily treat toothache pain safely.

Methemoglobinemia in bronchoscopy: a case series and a review of the literature

BACKGROUND

Methemoglobinemia results from oxidation of ferrous iron to ferric iron within the hemoglobin molecule. This molecule cannot bind oxygen and increases the affinity of normal hemoglobin for oxygen, which results in decreased oxygen offloading in peripheral tissues. At elevated levels, methemoglobinemia can cause dyspnea, cyanosis, and even death. Common local anesthesia agents have been correlated with methemoglobinemia. Bronchoscopy is a commonly performed clinical procedure which uses topical application of these anesthetics to provide patient comfort. Methylene blue is an agent thought to help reverse the effects of methemoglobinemia by facilitating the methemoglobin reductase system.

METHODS

Using multiple search engines including PubMed and the Cochrane Database, available data on cases of methemoglobinemia after bronchoscopy were pooled. Adult and pediatric cases were considered.

RESULTS

Eleven cases were identified. Cases occurred from 1977 until present. Data gathering was complicated by the fact that a consistent reporting system was not used across cases. Arterial blood gas data and CO-oximetry reported levels of methemoglobin were reported where available. No patients died from methemoglobinemia. The most common finding across all patients was decreased peripheral oxygen saturation. Cyanosis was also frequently reported. There was a disparity between the low peripheral oxygen saturation which was reported and the pO(2) on the arterial blood gas. Dose and type of anesthetic agent varied widely across studies.

CONCLUSIONS

Using topical anesthetic during bronchoscopy appears relatively safe. No fatalities from methemoglobinemia after bronchoscopy have been reported. A high suspicion for methemoglobinemia is required in patients who develop hypoxia or cyanosis postprocedurally. Access to CO-oximetry can confirm the diagnosis but the clinical picture is often sufficient to proceed with methylene blue treatment or observation, based on how severely the patient is affected. Patients who return to baseline can be considered for discharge home.

Liposomal-benzocaine gel formulation: correlation between in vitro assays and in vivo topical anesthesia in volunteers

The aim of the present study was to characterize a liposome-based benzocaine (BZC) formulation designed for topical use on the oral mucosa and to evaluate its in vitro retention and permeation using the Franz-type diffusion cells through pig esophagus mucosa. To predict the effectiveness of new designed formulations during preclinical studies, a correlation between in vitro assays and in vivo efficacy was performed. Liposomal BZC was characterized in terms of membrane/water partition coefficient, encapsulation efficiency, size, polydispersity, zeta potential, and morphology. Liposomal BZC (BL10) was incorporated into gel formulation and its performances were compared to plain BZC gel (B10) and the commercially available BZC gel (B20). BL10 and B10 presented higher flux and retention on pig esophagus mucosa with a shorter lag time, when compared to B20. BZC flux was strongly correlated with in vivo anesthetic efficacy, but not with topical anesthesia duration. The retention studies did not correlate with any of the in vivo efficacy parameters. Thus, in vitro permeation study can be useful to predict anesthetic efficacy during preclinical tests, because a correlation between flux and anesthetic efficacy was observed. Therefore, in vitro assays, followed by in vivo efficacy, are necessary to confirm anesthetic performance.

A sticky situation: methaemaglobinaemia in a hand trauma patient

We describe a case of methaemoglobinaemia (MtHb) in a previously healthy 39-year-old gentleman who presented with a traumatic glass laceration to his right wrist that required emergency surgery to control bleeding and repair his ulnar artery. The MtHb was noted on blood gas analysis by the anaesthetist after the patient had a drop in arterial oxygen saturation under general anaesthetic. We initially suspected the lidocaine local anaesthetic injected proximal to his wound for pain control in the emergency department an hour preoperatively, but then discovered that the patient was a recreational user of 'poppers' and had in fact been using these drugs just before his injury and hospitalisation. The patient's condition stabilised overnight with conservative management. Given how commonly hand surgeons and other clinical staff use local anaesthetics, we reviewed the literature on this uncommon, but potentially fatal, complication, its causes and evidence-based management.

Acquired methemoglobinaemia

Acquired methemoglobinaemia is a relatively rare condition and, therefore infrequently encountered in acute medical practice. Suspicion of the condition may be triggered when the measured PaO2 is 'out of keeping' with the oxygen saturations that are discovered with pulse oximetry. We describe two separate cases of acquired methemoglobinaemia secondary to the recreational use of alkyl nitrites ('poppers'). The patients presented at separate times to two different teaching hospitals in London, UK. The similarity of these cases has led the authors to conclude that a raised awareness of this potentially fatal condition, and its association with a widely-available recreational drug, is necessary to ensure a correct and timely diagnosis.

Dyed but not dead

The use of vital blue dyes in sentinel lymph node mapping and biopsy is gaining popularity in the surgical management of cancer. However, intraoperative use of these dyes has associated risks for the patient. This case report and review of the literature present current medical knowledge about one of the vital blue dyes, isosulfan blue, and the associated clinical risks of this dye when used in the perioperative management of patients who undergo sentinel lymph node mapping and biopsy.

Benzocaine-induced methaemoglobinaemia: a case study

Benzocaine is a widely used topical anaesthetic and has been reported to cause toxic methaemoglobinaemia in otherwise healthy individuals with no predisposing risk factors. This article reports on a rare case of benzocaine-induced methaemoglobinaemia following adenotonsillectomy in a 5-year-old girl. Topical benzocaine was applied orally for the relief of postoperative wound pain on the eighth postoperative day. Two hours after application, generalized cyanosis, mild dyspnoea and some degree of agitation developed. The methaemoglobin level was 38.5%. Treatment with methylene blue was initiated immediately. Symptoms completely disappeared 4 hours after initiation of methylene blue therapy. The further course was uneventful. Therefore, all health professionals should be aware that topical anaesthetics after surgery can induce methaemoglobinaemia in children, even after a prolonged interval, and especially when applied on wound surfaces.

Liposomal encapsulation improves the duration of soft tissue anesthesia but does not induce pulpal anesthesia

STUDY OBJECTIVE

To compare the topical and the pulpal anesthesia efficacy of liposomal and plain benzocaine formulations.

DESIGN

Double-blinded, randomized crossover study.

SETTING

University ambulatory dental center.

PATIENTS

30 ASA physical status I volunteers.

INTERVENTIONS

Volunteers received, in three different sessions, topical application of liposome-encapsulated 10% benzocaine (LB10), 10% benzocaine gel (B10), and 20% benzocaine gel (B20) in the right maxillary canine mucobuccal fold.

MEASUREMENTS

Pain associated with the needle insertion was rated by visual analog scale (VAS) and the duration of topical anesthesia was recorded. Pulpal anesthesia was evaluated using an electric pulp tester.

MAIN RESULTS

VAS values (median, 1st - 3rd quartiles) were 17 cm (11 - 25), 14 cm (3 - 22), and 21 cm (9 - 21) for B10, LB10, and B20, respectively. No differences were noted among the groups (Friedman test; P = 0.58). Soft tissue anesthesia was also not different. The LB10 [10 (8 - 12) min] showed longer soft tissue anesthesia (Friedman test; P < 0.01) than the other agents [B10 = 8 (5 - 10) min, and B20 = 7 (6 - 9) min]. None of the topical benzocaine formulations tested induced pulpal anesthesia.

CONCLUSIONS

The encapsulation of benzocaine into liposome increased the duration of soft tissue anesthesia. However, it did not induce pulpal anesthesia.

Unusual cause of severe toxic methemoglobinemia in an infant: a case report

Toxic methemoglobinemia is an uncommon blood disorder induced by exposure to certain oxidizing agents and drugs. In severe cases, this condition may rapidly lead to major cardiopulmonary compromise and constitutes an emergency requiring prompt recognition and early management. We report an unusual case of severe toxic methemoglobinemia following wide cutaneous application of a pomade containing benzocaine, resorcin, and oxyquinoline (Nestosyl®) in an infant.